Pepper: PPB_VideoEncoder should be 'Dev' only for now.

ppapi/api/ppb_video_encoder.idl

 /* Copyright (c) 2015 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /**
  * This file defines the <code>PPB_VideoEncoder</code> interface.
  */
 
 [generate_thunk]
 
 label Chrome {
-  M42 = 0.1
+  [channel=dev] M42 = 0.1
 };
 
 /**
  * Video encoder interface.
  *
  * Typical usage:
  * - Call Create() to create a new video encoder resource.
  * - Call GetSupportedFormats() to determine which codecs and profiles are
  *   available.
  * - Call Initialize() to initialize the encoder for a supported profile.
@@ skipping 197 matching lines @@
    * callbacks will still run, reporting <code>PP_ERROR_ABORTED</code> . It is
    * not valid to call any encoder functions after a call to this method.
    * <strong>Note:</strong> Destroying the video encoder closes it implicitly,
    * so you are not required to call Close().
    *
    * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
    * encoder.
    */
   void Close([in] PP_Resource video_encoder);
 };